Slide action switch mechanism



June 4, 1968 w. E. WARD 3,

SLIDE ACTION SWITCH MECHANISM Filed Aug. 29, '1966 2 Sheets-Sheet 1 June 4, 1968 w. E. WARD 3,387,106

SLIDE ACTION SWITCH MECHANISM Filed Aug. 29, 1966 2 Sheets-Sheet 2 United States Patent 3,387,106 SLIDE AIZTIGN SWITCH MECHANISM Williiarn Edward Ward, Ilford, England, assignor to The Piessey Company Limited, illford, England, a British company Filed Aug. 29, 1966, Ser. No. 575,599 Claims priority, application Great Britain, Aug. 27, 1965, 37,029/ 65 6 Claims. (Cl. 200166) ABfiTRACT OF THE DHSCLOSURE An electric switch includes a springy wire forming a movable contact. When suitably actuated an end of the wire is movable against or away from an inclined edge constituting a fixed contact, the wire sliding along the edge so that wiping action occurs. The fixed contact edge may abut an edge of insulating material, transition of the Wire between the two edges constituting operation of the switch.

This invention relates to electric switches.

It relates specifically to the provision of a muting switch for a record player by means of which an output from a pick-up may be interrupted at all times except when a pick-up stylus is in a position to be in contact with a record groove.

In a record player a pick-up is usually supported on a tone arm which is linked by mechanism responsive to movements of the tone arm to a muting switch which enables the output from the pick-up to be interrupted. The pick-up will thus produce an output only when the tone arm is moved wtihin a predetermined arc.

According to one feature of the invention a muting switch for the purpose set forth above comprises a movable contact in the form of a springy Wire which cooperates with a fixed contact including an inclined edge along which the movable contact slides or wipes during make or break operation of the contacts the movable contact being arranged for actuation by a pivoted actuating member. The actuating member may conveniently be biased to a normal position by a spring which forms an integral part of the wire movable contact. Means may be provided to enable the contacts to be joined in circuit between an amplifier and a pick-up. The means enabling the amplifier to be connected may be a plug socket, a resilient contact in the plug socket being provided by part of the spring contact. The means enabling the pick-up to be connected may be a connecting tag which forms part of the fixed contact.

By way of example an embodiment of the invention will be further explained with reference to the drawings accompanying the specification in which:

FIGURE 1 shows a plan view of a muting switch for a stereo pick-up in which two output channels from the pick-up are switched simultaneously and two sockets are provided for enabling the switch to be connected to an amplifier,

FIGURE 2 is a side view of the muting switch,

FIGURE 3 is a view from one end thereof, and

FIGURES 4, 5 and 6 are similar views of an alternative form of muting switch.

The switch comprises a platform 1 to which is attached a mounting socket 2, An actuating member 3 is supported on the platform against a ledge 4 and the actuating member may thus pivot about this ledge and be moved through a small angle away from the platform 1. A stop 5 is provided on the platform to prevent the actuating member 3 from being moved through too great an angle. The actuating member 3 is biased towards the position in which it lies against the platform 1 by means of two U- shaped springs 6. A shorter arm 7 of each U-shaped spring bears against the actuating member 3 and tends to hold this against the platform 1. Each U-shaped spring 6 also acts as an inner contact 8 of a socket 9. Two of the sockets 9 are mounted on the platform 1 and these enable an input lead from an amplifier to be connected by means of a suitable plug to the muting switch.

A longer arm of the spring 6 acts as a moving contact 10 and this may be lifted away from a fixed contact 11 mounted on the platform by means of the actuating member 3. Each fixed contact 11 is provided with an inclined edge 12 against which the moving contact 10 will rub as contact is established. This inclined edge 12 ensures that the contacts have a self-wiping action and the contact surface will thus be kept clean and free from dirt. To the fixed contacts 11 tags 14 are attached by means of which the fixed contact can be connected to an output lead from a pick-up. The tags 14 are mounted on the platform 1 andare additionally connected to outer contacts 15 of the sockets 9 so that these sockets may be suitably earthed. The U-shaped springs 6 are held against the platform 1 by tags 13 to which the other output lead from the pick-up is connected. The platform 1 is formed of electrically insulating material.

In operation, the muting switch will be fitted to a record player beneath a record turntable where the actuating member may be moved mechanically as the tone arm passes through its predetermined arc. The relevant tags on the platform 1 are connected to output leads from the pick-up and input leads from an amplifier or amplifiers are connected to the sockets 9. When a pick-up stylus has entered a record groove during operation of the record player the actuating member 3 will be lifted away from the platform 1 causing the moving contacts 10 to break contact with the fixed contacts 11. During operation of the record player the pick-up output will thus be passed through the muting switched to the amplifier. Before the pick-up stylus reaches the end of the groove in the record however the actuating member 3 will be allowed to return to a position parallel to the platform 1 causing the moving and fixed contacts to come together and the pick-up output leads to be short-circuited. Thus when the switch is in this position there will be no output from the pick-up to the amplifier.

The muting switch illustrated in FIGURES 1, 2 and 3 is shown in a push-to-break construction. The switch may alternatively have a push-to-make construction and one form in which this may be arranged is shown in FIGURES 4, 5 and 6. Parts of the switch of FIGURES 4, 5 and 6 that are similar to the switch of FIGURES l, 2 and 3 have been given the same reference numerals.

A minor difference of construction between the switches is that in the embodiment shown in FIGURE 4, the shorter arm of the U-shaped spring 6 does not reach the actuating member 3 so that the actuating member is biased towards the platform 1 solely by the effect of the longer arm of the spring 6.

The longer arm of the spring 6 passes through a triangular hole 16 in a fixed contact 17. The fixed contact 17 acts in a somewhat similar way to the fixed contact 11 in FIGURE 3. When the longer arm of the spring 6 is lifted by the actuating member 3 it moves towards an apex of the triangular hole 16 and makes contact with an inside inclined edge of the hole. When the actuating member 3 is in its rest position the spring 6 moves towards a base of the triangular hole 16 and then is carried away from the inside edge of the hole by a fixed wedge 18. The fixed wedge 18 is formed of an electrically insulating material and conveniently this may be made at the same time as the platform 1 and bracket 2 by a plastics injection moulding operation.

The fixed wedge 18 thus acts to hold the spring 6 away from making contact with the inside of the triangular hole 16 when the actuating member 3 is at rest. However, when the member 3 is actuated the spring 6 is moved along the wedge until the spring slides off the wedge and can make contact with the inside of the hole 16. Further movement of the actuating member 3 will lift the spring 6 towards the apex of the hole 16 and eventually the movement of the actuating member will be limited by the stop 5.

The fixed contact 17 is joined to a tag 14 mounted on the platform 1 and also to the outer contact 15 of the socket 9.

The descriptions of the parts of the switches have been given generally in the singular but it will be clear from the drawings that both types of switch are of the double-pole type and thus many of the parts are duplicated in each switch. The contact-making parts of each type of switch move together with a wiping motion so that these contact surfaces will tend to have a self-cleaning action when in service.

The foregoing descriptions of embodiments of the invention have been given by way of example only and a number of modifications may be made without departing from the scope of the invention. For instance the method of connecting the amplifier to the muting switch has been described as by means of a plug and socket connection. It is clear however that other means such as a soldered or a screw terminal connection might alternatively be used.

The muting switch of the invention has been found to be quite readily assembled from a small number of separate parts. The use of integral mounting sockets by means of which the pick-up may be connected to an amplifier avoids the need for fitting a separate mounting socket and of providing mounting means for this socket and also eliminates the need for connecting wire leads between the separate socket and the mounting switch. The integral socket thus requires no separate connections to be made to the muting switch and thus reduces the time required to wire up a record player as well as providing greater reliability by reducing the number of wire joints required.

The muting switch may be made of small dimensions and then the shortness of the connections in series with the amplifier input leads will help to reduce the possibility of electrical interference entering at this point in the amplifier circuit.

What I claim is:

1. A switch mechanism comprising a platform formed of electrically insulating material; a displaceable actuating member supported on said platform; a fixed contact having an inclined edge supported on said platform; a spring secured to said platform and engaging said actuating member; a moving contact formed of a displaceable end of said spring slidably engageable against said fixed contact inclined edge, said moving contact being displaceable along said fixed contact inclined edge and into and out of engagement with said fixed contact in response to the displacement of said actuating member.

2. A switch mechanism as claimed in claim 1, including a fixed wedge formed of electrically insulating material, said moving contact being slidably engaged along said fixed wedge in response to the displacement of said actuating member into engagement with the inclined edge of said fixed contact.

3. A switch mechanism as claimed in claim 1, wherein said spring biases said actuating member against displacement thereof.

4. A switch mechanism as claimed in claim 1, for cooperation between a pick-up and an amplifier, including a plug socket, said spring passing therethrough, and connecting means between said plug socket and said amplifier and engaging said spring, whereby said amplifier and said moving contact are in electrical connection.

5. A switch mechanism as claimed in claim 1, in which the actuating member is pivoted for movement with respect to said platform.

6. A switch mechanism as claimed in claim 5, in which said platform includes a stop effective to prevent the actuating member being moved too far from a rest position.

References Cited UNITED STATES PATENTS 2,587,458 2/1952 Fritts 2O0166 2,761,936 9/1956 Verkuil 200-166 2,789,172 4/1957 Happe 200-166 3,059,059 10/1962 Bernutz et al. 200-166 ROBERT K. SCI-IAEFER, Primary Examiner. H. O. JONES, Assistant Examiner. 

